Burner installation for boilers



Au ye, 1938.

Filed Dec. 14, 1935 2 Sheets-Sheet l mask/2% Imus HzzhafbA. Sharp a. 2

xv w t 3 r X E M E v wuzmam O a Q Aug. 9,1938, R. A. SHARP 2,126,417

- EURNER INSTALLATION 'FOR BO ILBRS 7 Filed Dec. 14, 1935 Y 2 Sheets-Sheet 2 Bishard A. 5h 27:

UNITED STATES PATENT OFFICE BURNER INSTALLATION FOR- BOILERS Richard A. Sharp, Milwaukee, Wis., assignor to Milwaukee Reliance Boiler Works, Milwaukee,

This invention relates to improvements in oil burners, and more particularly to burner installations for steam generating boilers of the Wis., a corporation of Wisconsin Application December 14, 1935, Serial No. 54,371

6 Claims.

fire tube type suitable for portable mounting.

Boilers of this character are generally heated by hydrocarbon or oil burners, and heretofore, diiiiculty has always been experienced in providing aproperly controlled secondary air supply.

It is therefore an object of this invention to provide a burner installation of the character described which has simple and efficient means for supplying controlled secondary air to be injected into the main fire tube or combustion chamber of the boiler together with the fiame from the burner.

Another object of this invention is to provide a novel and improved construction for supplying controlled secondary air for burner installations of the character described which coacts with the nozzle of the burner to insure proper comingling of the secondary air with the flame or combustion gases projected from the burner nozzle.

Another object of this invention is to provide means for supplying controlled secondary air for burner installations of the character described which is particularly applicable to installations in which the burner is movably mounted to swing into and out of its operative position.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims. The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a longitudinal sectional view through a boiler embodying this invention;

Figure 2 is an enlarged detail sectional view showing the manner of introducing the secondary air on the plane of the line 3-3;

Figure 4 is a sectional view through Figure 1 on the plane of the line 4-4;

Figure 5 is a sectional view through Figure 1 Figure 3 is a sectional view through Figure 1 Figure 6 is a top view of a portion of the boiler to show the manner in which the burner is mounted; and V Figure 7 is a sectional view similar to Figure 2 illustrating a slightly modified embodiment of 5 the invention.

Referring more particularly to the accompanying drawings in which like numerals indicate like parts throughout the several views, the numeral 5 designates the cylindrical outer shell of the boiler in which headers 6 and I are secured inwardly of its extreme ends. The chambers 8 and 9 formed outwardly of the headers 6 and 1, respectively, are closed by removable end walls l0 and II, respectively.

Connecting the headers 6 and l and communicating the chambers 8 and 9 is a main duct or fire tube I2, which is disposed coaxially within the boiler, and a plurality of small tubes l3. The space within the shell between the headers 6 and and around the outside of the tubes 2 and I3 provides the water space which is connected with the interior of a steam drum 4 as at 5.

Extending across the chamber 9 in line with and forming substantially a continuation of the main fire tube I2, is a cylinder |6 of refractory material. This cylinder l6 projects out through the removable end wall II and has a refractory end plate or wall disposed across its outer end.

Extending through this refractory end plate I! is an inwardly fiared centrally located metal lined opening |8 through which a flame or combustion gases may be projected into the tube I2 from the nozzle IQ of an oil burner, indicated generally by the numeral 20. The manner in which the burner 20 is mounted, and the manner in which secondary air is provided to insure proper and efficient combustion will be hereinafter more fully described.

The opposite end of the main fire tube I2 opens into the chamber 8 above a horizontal partition wall 2| formed of refractory material, and beneath an inclined transverse partition wall 22, also formed of refractory material. Between the partition walls 2| and 22, the removable end plate ||l is lined with a refractory surface 23 and the curved walls of the shell between the partition walls 2| and 22 are likewise lined with refractory material 24 (see Figure 3). Consequently, the main fire tube discharges into a chamber completely lined with refractory material and extending to opposite sides of the main duct to communicate with the two adjacent upper groups of tubes I3.

The flame or combustion gases projected into the main tube I2 are thus conducted into these upper tubes I3 through which it travels forwardly into the chamber 9 above a transverse partition wall 25. The curved sides of the chamber 53 above the partition wall 25 are preferably lined with refractory material 26, but the partition wall 25 need not be so protected inasmuch as the gases at this point have been cooled to some extent.

The compartment of the chamber 9 into which the combustion gases are discharged by the upper tubes i 3 extends low enough to communicate with two transverse rows of tubes I3 beneath the main tube I2 through which the combustion gases are again conducted back into the chamber 8 and into the compartment thereof beneath the partition wall 2I. From this compartment the lowermost rows of tubes I3 conduct the combustion gases forwardly to the compartment of the chamber 9 beneath the partition 25 from which an exhaust flue 21 leads.

Hence, it will be seen that the boiler is of the multiple pass type and that the exhaust is at the lowest point of travel thereby insuring maximum heat transfer.

The oil burner 20, as particularly shown in Figure 6, is mounted to swing to and from an operative position by means of a hinge 28 carried by an annular duct 29 mounted on the refractory end plate IT. The central passage 30 formed by the inner peripheral wall of the annular duct 29 has its inner end in line with the inwardly flared opening I8 through the refractory end plate.

The walls of this central passage 30 flare outwardly so that the total passage consisting of the inlet opening I8 and the passage 30 forms a venturi into which the discharge nozzle I9 of the burner projects.

The interior of the annular duct 29 is connected with the discharge of a blower 3| through a duct 32. The air forced into the annular duct by the blower is the secondary air supply and is discharged therefrom through an inwardly tapered annular opening 33 and a circumferential series of ports 35 formed in the outer wall 36 of the duct 29.

Circumscribing the series of ports 35 is a packing element 31 fixed to the wall 36 and with which the adjacent surface of the burner engages so as to leave a space communicating with the passage 30 through which the air issuing mm the ports 35 enters the passage 30 to be projected into the main fire tube I2 along with the combustion gases or flame projected from the burner nozzle.

The ports 35 having a total area considerably less than that of the annular opening 33, it follows that the main body of the air supplied by the blower 3I is discharged through the annular opening 33.

While the, construction can be of modified form, that shown has been found desirable and practical. In this construction the outer wall of the annular opening 33 is defined by a metal ring 38 welded to the plate 39 which forms the inner wall of the annular air chamber 29, and the inner wall of the annular opening 33 is defined by a central enlargement on a casting 4B which is so shaped as to also define the Venturi-like passage 30.

This casting 40 is secured to the outer wall '38-of-the air chamber 29-as at =4I so that these parts form substantially one unitary structure.

The inwardly tapered formation of the annular opening 33 insures good admixture of the air and fuel, but the operation of the burner may be further improved by substituting in place of the annular opening 33 a plurality of circumferentially arranged apertures 42 as shown in the modified embodiment illustrated in Figure 7. These apertures 42 are formed in a flange 43 on the casting 40 and to which the inner wall 39 of the air chamber is fixed as at 44. These apertures may be round holes drilled through the flange 43, or if desired, they may have an elongated or arcuate cross section or shape.

In either event, the apertures are arranged helically as indicated by the dotted lines in Figure 7 so as to impart a twisting or whirling motion to the air discharged therethrough to thereby further insure proper comingling of the air and fuel.

From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent to those skilled in the art to which this invention appertains, that inasmuch as thespeed of the blower, and consequent ly, the volume of air delivered thereby, is readily governed, the secondary air supply is at all times under control, as distinguished from past constructions in which the secondary air which is necessars for complete combustion and eflicient operation was merely drawn into the combustion chamber by a natural draft; and that the present construction is a substantial improvement over this past practice.

What I claim as my invention is:

1. In a combustion apparatus for use with a combustion chamber having a front Wall provided with an inlet opening: a tubular member projecting into the inlet opening and forming a venturi; an annular air chamber encircling the o te d portion of said tubular member and formed in part by that portion of the tubular member which extends outside of said front wall; a hydrocarbon burner having a nozzle arranged to discharge into the venturi; said air chamber having an air outlet for discharging air into the combustion chamber to comingle with the fuel projected into the combustion chamber through the venturi; and means for supplying air under pressure to said annular chamber.

2. In a combustion apparatusfor use with a combustion chamber: a closure for the front of the combustioncharnber having an inlet opening therethrough and a plurality of air inlet ports encircling said inlet opening; an annular air duct engaging the outer face of said closure with its inner peripheral wall forming a passage in line with said inlet opening, said annular air duct having the air inlet ports opening thereto and having air discharge ports in its outer wall opposite said closure; a hydrocarbon burner having a discharge nozzle projecting into said passage to direct fuel into the combustion chamber, said burner having a wall coacting with the adjacent outer surface of the annular duct to provide a passage leading from the air discharge ports in said outer wall of the duct to the passage through the duct which aligns with said inlet opening so that air discharged from said ports enters the combustion chamber along with fuel, and air discharged through said air inlet ports enters the combustion chamber around the fuel; and-means to supply air under pressure to said annular duct.

3: In a combustion apparatus for use with a combustion chamber: an outer wall for the combustion chamber having-a central inlet opening and an air-inlet port encircling said opening; a hydrocarbon burner having a nozzle pro- Jecting into said central inlet opening; an annular air chamber overlying the outer face of the closure and having the burner nozzle extending through its hollow central portion; said annular air chamber having the air inletport opening thereto; and means for supplying air under pressure to said annular air chamber.

4. In a combustion apparatus for use with a combustion chamber having an outer wall provided with an inlet opening: a tubular structure fitted into said inlet opening and having a central venturi extending directly therethrough and an air inlet port encircling said venturi; an annular air chamber encircling the outer end portion of said tubular structure and having said annular air inlet port opening thereto; means'for supplying air under pressure to said annular air chamher; and a hydrocarbon burner having a fuel spraying nozzle projected into the central venturi.

5. In a combustion apparatus for use with a combustion chamber provided with an inlet opening: a closure wall for said combustion chamber opening, means carried by said closure wall and extending inwardly toward the interior of the combustion chamber and outwardly away from the wall to define a central venturi, said means being provided with an air inlet port encircling the inner end portion of the venturi and pointed inwardly toward the interior of the combustion chamber; another wall joined to the outer face of said closure wall and encircling the outer end portion of the central venturi to form an air chamber encircling said outer end portion of the venturi withthe air inlet port opening thereto; means for conducting air under pressure to said chamber; and a hydrocarbon burner having a fuel spraying nozzle arranged to discharge into the venturi.

6. In a combustion apparatus for use with a combustion chamber provided with an inlet opening: a closure wall for said combustion chamber opening; an inwardly directed tubular part carried' by said wall and extending inwardly toward the combustion chamber to define the inner end of a central venturi and having' an inwardly converging air inlet port formed in the wall of said Venturi part around the venturi; means carried by the closure wall and extending outwardly therefrom away from the combustion chamber to define the outer end portion of said central venturi; and an annular air chamber encircling said outer portion of the venturi, said air chamber having the air inlet port opening thereto; means for supplying air to said air chamber; and a hydrocarbon burner having a fuel spraying nozzle arranged to discharge into the venturi.

.- RICHARD A. SHARP. 

